A Method for the Estimation of the Penetration of Biologically Injurious Solar Ultraviolet Radiation into Natural Waters

Abstract

In spite of the critical importance of attenuation data for the biologically potent short wavelength solar UV (primarily UV-B 280–320 nm) there are very few published data on the penetration of these wavelengths in freshwaters and only limited observations in marine waters, Smith and Tyler (1976). In the absence of extensive quantitative data, very erroneous impressions of the shielding of aquatic organisms by the water have arisen. Although superior methods of measuring or calculating attenuation are needed, and will doubtless be developed, certain regularities in the optical properties of natural waters have been observed and the use of these characteristics is proposed. The attenuation of solar UV radiation as weighted by the Robertson sensor (UV-RB) in a wide variety of natural waters has been measured. The waters surveyed included very clear oceanic and freshwaters, marine locations of high productivity, bays and estuaries, large and small lakes, reservoirs and streams. Various other measurements were made at the time of the UV-RB attenuation measurements.